Pneumatic tool



May 31, 1932. 'l F. nh. SLATER PNEUMATIC TOOL Filed Dec` 3, 1931Patented kMayY 31;!'1932y i FRED? v rNY, or JERSEY CITY, NEW JERSEY,CORPORATION OF nawarmsnr rNEUMATrc .'rooL` applicati@ and December3,1931, seria; No. 578,665,

This invention relates to pneumatic: tools, but :more particularly to avalve mechanism for tools Oflthis character.

Y` One object of vhegimvention is to retain the distributing valveiirrnly seated. in its limiting `positions irrespective of theactionef'the piston which it controls.I

@Other Objects-Willibe in ipart Vobvious and y in jp'artffpinted outhereinafter# f :In the accompanyi lg drawings illustrating H `L n Y therinvention and in which lsimilar reference characters refer to similarparts, f A 'Figure iis-ia longitudinal elevationin sec g tion Of' aportion of a rock drillequipped with y., valve mechanism constructed inVaccordance with the Apractice of theinventionand Figure 2 isa.transverse view taken throufh reetifon indicated by the arrows.

Y' r-Referring moreparticnlarly tethe drawV Yings, Adesignatesingeneral, a rock.y drill eemprising a cylinder l B having f a ypietenvchamber C te accommodate a reciproeatery hammer pi'stengl). The pistonD yis ofthe differential typehavinga head "Fi and a stem G at the frontend of the head extending: slidablythrough the rvfrontend' of the cyl-vinder' B for delivering blows against a Workingimplement, such as a'drill' steel (not shown); I In-@the cylinder Bris a free exhaust HVwhichy controlled bythe head F of K L the; plate Xand the cylinderBtQtheLron-t end' ofthepistonVV chamber Offer admitting the "piston El;

yWliich extendsa rielbar L tofinterlockingly cngagetherpiston D in aWell known manner fer imparting rotarygfnievement thereto. At therearend of' the. rifle bar Lirs'a head O which seats iiponfthefbackcylinderWasher J and carries rpawlis P fori engagement with teeth Qo a ratchet;ring encircleskk the head OJ@ Y Y f v The ratchet ring vE and theheadQin: the

Y present.insta-nce;` are arranged 'within a'hore yerreeess'Sini/che`front end of' a back Twhich risse-ated on the'back cylinderwasher y,Jfand which may be. secured A te theeylinder "B in any suitable'manner;V

distribution ef-pressiire flnid 'tothe ends of the piston chaniber Cfoi-'actuating the Piston D S efeted `by valve mechanism Ul arranged, inthe present instance, onthe side of thecylinder Band comprising a valvechestz V which preferably includes a y pair of plates W and); bolted, orotherwisesecillator'y iilate' distributing :valve ZV which fis heldagainst vlongitudinal lmovement in the,

valve chamber Yfby a pin biseatedinthe Y plate 'W and extending into anaperture c in the lvalve The Oppositely extending Wings Zand e of thevalve are tapered ,from

the' tran'sYersefmedianline' ofthe valve te-Y i wards' the enteredges,thereof in 'the usual manner and are kadapted to'seatupon seatingsurfaces f endg,` respectively,- en the plateX.

Leading frmnthe seating surface f tothe rear end of A'the piston chamberGrandezztending threnghfthepl'ateX and the cylinder B5 Vis agrearfinletpassage h Lthrough which pressure Afluid flows into the rear end'ofthepiston chamber crfdiving tliezpiston D'forg Wardly on itsv rWorkingstroke, andsaid inlet; passage'is'controlledabythe wingelei the valve;

Similarly, yfrom the v:seating surface. fleads al front inletfpassagejwhich is controlled by' i the wing 'fl of the valve andv extends throughpressure fluid theretobtoy drive thel piston reairwvardlyrr intoaboreein the plate W. A passage pin the :pla-te W conveys. suchpressurefluidv inta the valve charnherl Y- and yis edntrl'led faf T he rockdrill so position illustrated in'Fignre 1,v wherein the WingV e' of thevalve: Yis raised andtfhepistorr lDflies. rearwardly-ofthe exhaust portyHf ,pressurel luid clvvs Over'the raised end of the l wing e throughthefifnlet passage ih into the far deSCribedfinayfbe-e y a known type Ofwhichv the -operation;` is Fas fallo-.Ws lith thedistribntinggvalvebZ inthe? meterla, or EASTON, rENNsYLvANm, Assi'GNOR iro manson-RANDycoin-...Q

y C1 waraiy. 'rov this rear end of the piston rchamber C to drive thepiston D forwardly on its working stroke.

t After the piston D covers the exhaust port H the air in the front endof the piston cham- 5 ber C'will be compressed and will act against theseated wing d of the valve. Y

When the compression in the 'front end of the piston chamber reaches avalue together with the force of the suction created by the lo pressureffluid flowing over the wing e eX- ceeds the pressure acting on the uppersurface Y of the seated wing d, the valve Z will be rocked to its otherylimiting position.

the piston chamber will then be cut offl and pressure fluid willfflowover the raised end of the vwing e and act against the front end ofthe'valve F ofthe piston D to'drive said piston rearwardly. 1

f Normally,in theabsenceof anyforce tending to retard the free movementof the piston D, the piston may reciprocate at a rapid rate and theaction thereof, together with that'of Y ythe distributing valve Z, willbe substantially as as'hereinbefore described.' kIn other kwords, thepiston D'will travel its full nominal stroke and will deliver a yheavyblowk against the working implement during each cycle ofL movement ofthe pistonl andV of the valve Z. Thereare instances during the operationof tools of this character when, due to irregularities in the rock beingdrilled, the working im- Dlement-becomes stuck or bound in thedrill holeto such an extent as to interfere seriously withthe rotary movementAthereof, such as may be induced by the rotation mechanism including therifle bar L, its pawls P and the ratchet ring` f Such retardation of therotation mechanism, in consequence, effects the movement of thepiston'D.

f r'Whenever vthe working implement offers great resistance to theaction of therotation mechanism the piston D reciprocates at a reducedrate ofspeed and, as a result,any pressure fluid which leaks from thevalve chamber'Y beneathfthe seated end ofthe valve and into an yend ofthe piston chamber ,will therefore build up suflicient'pressure in thatend yofv the piston chamber to raise the'seated end of the valve. `Thepiston vD will then `be reversed without completingits stroke. In Yother words, the valve may be tilted before the piston head F hasuncovered the exhaust port H; f This is objectionable for the reasonthat the full force of which the piston D is capable .will then notfbeapplied to the working implement to wrest it freefrom `the rocksurface.y "i

f In view of thel foregoing facts it is contemplated 'to provide meansintended to assure the retention` of the valve Z in its limitingposition throughout all periods of operation ofthe tool until the pistonD has completed its nominalstroke,both forwardly and rear- They supplyof pressure fluid to-the rear end of f end thevalve chest, and

A whichis located rearwardly of thetransverse rmedian `line of therelief valve chamber 1',

75 opens into a recess 1J 1n the seating surface g.

Leading from the relief valve chamber r, at a point intermediate itsends, is a relief passage w which extends through the plate X andthecylinder B and opens to the atmosphere. Y

'Disposed in the relief valve chamber 1' is a relief valve a: whichcomprises-a pair of end heads jz/ anda connected` by a reduced stem 2.The front and rear endsof the valve 'constitute actuating areas-3 and 4,respectively, against which .pressure -fluid acts to throw thevalve'lfrom ,one limiting position to the other. y'Such pressure fluidis conveyed to theV frontend of the valve. chamber 1 by a passage 5vwhich communicates with the inlet passage I7',iand pressure fluid is`conveyed into vthe'rear-end of the valve chamber 1' from the inlet'passage h by a passage 6. Y i

The vmanner `in which'the relief valve a1 operates is as follows: Upon;the admission of pressure fluid into the ends of the piston chamber, asfor instance, when admitting pressure fluid tothe rear end of -thepiston chamber, a portion of the pressure fluid flowing. k'through .theinletl passage yL ypasses through they passage 6 into the rear end ofthe valve Lchamber 1' and acts. against the actuating surface-4 to` movethe valve ai. forwardly In this position of the valve :v the recess uwill be in communication with the atmos# phere through fthe port s, theintermediate portion ofthe valve 1' and the relief passage/w.' Anypressure fluid thenvleaking beneath the seated wing d of the valve willcscapeto the atmospherethrough these channels and only the compressionfromthefront end of the piston chamber Cvflowing through LUG the inletpassage j willact against a comthe piston has reached a position duringits 12tforward travel where it will uncover the exhaust port 5 When thepiston reaches this portion there will be a direct flow of pressurefluid from the valve chamber' through the piston lchamber and theexhaust port H and the suction of the pressure fluid flowing overthewing e, together with thecompression acting against the wingy d, willthen tip the valve.

In the new position of ythe valvepressure fluid ilows into the front endof the piston chamber C. i-iportion of such pressure fluid will flowthrough the passage into the front f end of r.the valve chamber?" andactagainst the actuating surface 3 to move the valve ,m

v rearwardly. n ln this position of the valve m passageH, whereupon thevalve Zwill again Y be shifted. l

distributing valve chamber, inlet passages leading from the distributingvalve chamber tothe cylinder, an oscillatory plate valve in 'thedistributing valve chamber to control the inlet passages, seatingsurfaces for the valvel having recesses therein, ports connecting therecesses with therelief valve chamber, a relief-.passage leading fromtherelief Avalve chamber to the atmosphere, a valve in the relief valvechamber to control communication between the ports andthe reliefpassage, and passages for conveyingy pressureV fluid from the inletpassages into the relief `valve chamber to actuate the relief valve.

Intestimony .whereof I have signed this specicatioi'i.l

FRED M. SLATER.

As will be apparent from'the foregoingk v description, onlycomparatively small lareas Y Vof the seated ends ,of the valve will beexposed to such pressure iiuid as may leak beneath the valve and,ofcourse, also to compression acting through ther inlet passagesassociated with the several ends of the valve chamber Y. It will furtherbe apparent that the valve m will be shifted in timed relation with thevalve Z to maintain a considerable portion of the seated posed toatmospheric pressure. The valve Z will,.in consequence, remain firmlykseated in its liinitiiig'positions and will not be tilted until thepiston D has reacheda position to uncover the exhaust port H,irrespective of Whether thefpiston D is reciprocating rapidly or at aslow rate of speed.

I claim: f

l. In a pneumatic tool', the combination of a cylinder and a pistonthereinfa valve Achest having a valve chamber, seating surfaces inthevalve chamber and havingre-v cesses therein, ya distributing valveV1n the -valve ,chamber for distributing pressure fluid to the cylinder,passages for communicating y the recesses with the atmosphere, and asec` ond valve movable in timed'relationv with the Vfirst saidvalveforcontrolling the passage.

a cylinder and a piston, a valve chest having a distributing valvechamber and a relief valve chamber, seating surfaces in the dis`tributing Vvalve chamber havingV recesses therein, ports connecting therrecesses with the relief valve chamber, a relief passageV leading fromthe relief valve chamberto the atmosphere, a valve inthe relief valvechamber to control communication Ybetween the Vports and thereliefpassage, and passages for conveying pressure fluid into the reliefvalve chamber for actuating .the relief valve upon endsof the valve eX-2. In apneuniatic tool, the combination of y the admission of pressureiuid to thecylinder.

- 3. lIn, a pneumatic tool,the combination of a cylinder and a pistontherein, a valve chest e having a distributing valve chamber and a im l

